Motor-protecting circuit-breaker.



EELS? AVAILABLE GOPY J. T. LEONARD.-

MOTOR PROTECTING CIRCUIT BREAKER.

APRLIFATION FILED MAILZO. 1913.

1,134,752, Patehted Apr. 6, 1915.

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I I I I Y UNITED STATES orEIoE.

Jenn r. nnonaan, oriwxcnr'ra, Kansas.

i To all whom it may concern:

Be it known that I, JOHN T. LEONARD, a citizen of the United States, residing at Wichita, in county-of Sedgwick and State of Kansas, have invented certain new and useful Improvements in Motor Protecting Circuit-Breakers, of which the following is a specification.

I. My inventlon relates to an improvementin motor protectlng circuit breakers and 1s more particularly adaptable for use with a multiphase motor. In the operation of m0-- tors of multiphase circuits there is always the danger of one or more of the phases becoming short circuited creating an abnormal circuit which tends to destroy the motor. When the motor is used in sewerage, water and other stations andis automatically stopped or started by a mechanically controlled switch the short-circuiting is particularly apt to occur or one or more of the fuses is apt to be blown-or melted out, dueto variations in the current. 7

One of the objects of my invention therefore is to provide-means whereby when the fuse in one of the line wires is. blown or melted out, the circuit of the phase or phases will be automatically. opened. This I accomplish by having a shunt circuit arranged so over each fuse and operating a solenoid switch in the circuit which controls the magnetic switch of the main line; thus if the fuse in any one of the line wires is-blown the circuit which closes the electro-magnetic switch is broken and this switch opens to open the main circuit, thus protecting the motor against abnormal circuit conditions in a'reliable, simple and eflicient. manner.

' This invention consists of certain novel features of construction and combinations of parts which will be hereinafter more fullydescribed and pointed out in the I claims.

In the accompanying drawings I have shown my invention embodied in concrete of the solenoid switches.

In the drawings I have shown my invention as applied 'to a 'tri-phase induction motor A, the main line wires 1, 2 and 3 being connected therewith for supplying the several hases. These wires have the fuses 4,

5 an 6 connected in their length. elec- Specification of Letters Patent.

. and 11.

ammatic view to show MOTOR-PROTECTING CIRCUIT-BREAKER.

tro-magnetic switch B is connected in the line wires 2 and 3 for controlling the circuit, and this switch is controlled by a circuit 7 in which a knife or other manually operated. switch 8 is provided to control the circuit to the electromagnetic switch B.

Gaps 9, 10 and 11 are formed in the line wire of the switch circuit 7. Solenoids 12, 13 and 14 are located adjacent these gaps and the armatures I5, 16 and 1.7 respectively have the bars or disks 18,19 and 20 carried in a position to rest upon 'and bridge the contacts of the gaps 9, 10 and 11 respectively in the switch circuit 7 when the solenoids are deenergized. The solenoid 12- is connected by wires 21 and 22 with the main line wire 1. The wire 21 being, connected on the one side of the fuse 4 and the wire 22 on the opposite side. Similar shunt circuits 23 and 24 connect the solenoids 13 and 14 'and the wires 2 and 3 respectively to bridge or Patented Apr. 6, 1915-. Application filed March so, 1913. Serial No. 755,659.

cut around the fuses 5 and 6 of these wires.

The shunt circuits to the solenoids are preferably of relatively high resistance and the fuses of materially less resistance; consequently the main portion of the circuit passes through the fuses 4, 5 and 6 and the solenoids 12, 13 and 14 do not under normal conditions receive an amount of current to sufiiciently energize them to draw the armatures into the coil and open To start the motor the switch 8 is closed, which completes the switch circuit 7, causing the electro-magnetic switch B to be thrown to close the main line circuit. As

the fuses 4, 5 and 6 are intact and the gaps 9, 1'0 and, 11 are bridged, the motor w1ll start and theelectro-magnetic switch will be held closed. When one of the fuses 4, 5 or the gaps 9, 10 V 6 burns out the current in that branch of the main line is shunted through the sole-- noid, drawing the armature into the coil and opening the gap in the swltch circult 7.

main line circuit.

A bell crank 25 is pivoted in juxtaposition- -Th.is causes the electro-magnetic switch B to be automatically opened and breaks the.

normal tendency as the solenoid is deenergized, due to the opening of the electro- 4 .30 circuit. e a .v v

3. The combination with a 'multi-phasemagnetic switch and consequent breaking; of the main circuit. v

Having fully described my' ffivention, what I claim as new and desire to secure by Letters Patent is-- v 1 1. Incombination with a multi-phase circuit having a fuse in each of the wires there of, an electro-magnet'ic switch of the underload break type positioned to open and 10 close said circuit wires, a switch circuit connected with said 'electro-ma'gnetic switch, and with the main circuit,and means connected between the-switch circuit and supply circuit whereby when one 'of the fuses burns.

' out, the switch circuit will bebroken and,

- the switch permitted to open, consequently opening the main circuit. I v i 2. The comb' ation with a multi-phase circuit having a-fuse in each of the wires there- '20 .of, an'electro-magnetic switchcof the under load break type, positioned to open and close said circuit wires, a switch circuit connected. with said electro-magnetic switch andiwith' the main circuit, and. mechanical '25 means operatedby a circuit connected with themain circuit to come into action when one ofthe fuses burns out, and break the switch-circuit, thereby permitting the switch to open and consequently opening the main circuit havingin each of the wires thereof an electro-magnetic switch of the under load break type positioned'to open and close said 5 circuit wires, a switch circuit connected with said electro-magnetic switch and with the main circuit, said' switch circuit provided .with a'plurality of gaps and shunt circuits, around each .of said-fuses,imechanical means 40 to normally close the "gaps of said switch circuit, thereby holding the electro-magnetic switch normally in closed position, and means connected in the shunt circuit to be energized when one of the fuses burns out for opening one ofthe gaps in the switch circuit, thus permitting the switch to open and consequentlyopemng the'imain circuit.

. 4. The combination with a multi-phase circuit having a fuse in each 'ofthe .wires thereoffan electromagnetic switch of the under load break type positioned to open and 'wlth the mainscircuit, said switch circuit having a plurality of gaps, mechanical and close said circuit, wires, a; switch circuit connectedwith said electro-magnetic switch means to normally close sald gaps whereby the connection through the swltch circuit is completed, and theswitch is held normally closed, a shunt circuit arranged around ,the v 1 fuse of each .wire, a solenoid connected in by each coil, a switch controlling the circuit the switch, and

-phase mo;

through all of the motor leads, a normally energized coil connected tonitlie supply circuit for the motor, and means for rel a and opening said last-named switch 0 ,de-

venergization of said normally energized coil,

the connection for said .coil includin the aforesaid switches controlled by 00' s in shunt with the respective fuses.

tors, comprising a no'-voltage coil in circuit with the m'otorleads, means controlled by the no-voltage coil for opening the motor circuitupon a drop of voltage, a fuse in- 6. A controlling means for poly-phase mof eluded in each motor lead, a high resistance coil in shunt with eac'hfus'e, and means controlled by each of said latter coils to openv v vthe circuit through the no-voltage coil on 1 H efie'ctive energizatlon of a second coil due to rupture. of the correspondingv fuse. p a In testimony whereof Iaffix my signature,

in the presence of two witnesses.

I Witnesses:

oni; T. LEONARD.

70 v with each of said fuses, a switch. controlled 

